BACKGROUND: This paper aims to develop a Chinese version of Universal Health Coverage (UHC) indices and to measure China's progress towards UHC. METHODS: Nineteen indicators were selected based on expert consultations to construct indices of accessibility and affordability to measure UHC. Data were drawn from health statistics yearbooks, nationally representative surveys, and health system reform surveillance. The index of accessibility includes absolute accessibility (to essential health services), relative accessibility (to hospital care) and people's subjective perceptions. The index of affordability includes absolute affordability (the incidence of catastrophic health expenditure, CHE), relative affordability (the composition of health expenditure), and people's subjective perceptions. RESULTS: The indices of accessibility and affordability both showed steady increases over the 17 years considered. Absolute accessibility had the most significant improvement (from 23.6 in 2002 to 73.8 in 2018), while the index of relative accessibility decreased from 81.4 in 2002 to 67.3 in 2018. The index of absolute affordability decreased significantly from 46.6 in 2002 to 30.5 in 2010 and then exhibited an increasing trend afterwards, reaching 52.1 in 2018. The index of relative affordability continuously increased during the observation period, from 35.3 to 75.4. CONCLUSIONS: China has made great progress in increasing the accessibility and affordability of health services since the health system reforms in 2009. However, integrating primary health care and hospital care and containing escalating medical expenditure to further reduce patients' financial burdens are key challenges for strengthening the Chinese health system.